The invention relates to a safety device to inhibit sleep by activating an alarm signal or other source of stimulation, in response to the relaxation of the muscles of the hand and fingers, such as occurs in conjunction with increasing drowsiness or sleep.
This invention relates more specifically to an apparatus which is worn on the human hand and which responds to the relaxation of the muscles of the hand and fingers to provide an alarm to warn a wearer of his impending sleep condition.
Such a device has numerous applications where it would be undesirable or unsafe to fall asleep, such as while smoking a cigarette in bed, or while operating an automobile.
The general concept of utilizing some changing physical characteristic brought on by drowsiness or sleep, to warn of impending sleep, is old in the art. By way of example, U.S. Pat. No. 1,881,878 to Nidy, discloses the use of a spring-loaded switch in the pilot's control stick of a plane. When the pilot begins to fall asleep, he relaxes his grip on the control stick. As a result, the spring mechanism closes a circuit which initiates an electric shock to wake up the pilot. As a more recent example of such warning devices is U.S. Pat. No. 3,861,349 to Conley, which discloses an arrangement wherein the driver of an automobile wears a glove to which a rigid or semi-rigid material, such as aluminum or plastic, is adhered. A nail, extending from the material, and pointed in a downward direction, is supposed to penetrate the thigh, thus awakening the driver. Alternatively, nails, which are pointed in the direction of the glove, are supposed to be forced into the glove fabric and awaken the driver if the driver's hand falls from the steering wheel and hits his thigh.
All the prior art warning devices have one or more disadvantages that are overcome in this invention. For example, many of the prior art warning devices are physically integrated within a part of a vehicle being controlled by the user. This integration substantially limits the flexibility of such a device since it becomes virtually impossible or impractical to utilize the warning device in other situations. However, the present invention provides a warning device that is worn by the user and that is readily utilized in a variety of applications, including that of preventing a driver or pilot from falling asleep at his vehicle.
Another disadvantage of the prior art is the unreliability of such devices. By way of example, the concept disclosed by Conley depends upon the premise that the driver of an automobile will drop his hand from the steering wheel onto his thigh when he falls asleep. The lack of reliability of this concept as a warning device, becomes readily apparent when it is realized that there is no assurance that the hand of the driver of an automobile will fall from the steering wheel as the driver falls asleep, and that there is no assurance even if the driver's hand does so fall, that it will land on the thigh of the driver or any other part of his body or that it will land in the proper position to cause the hypothesized pricking of the hand, disclosed by Conley.